A unifying point of view on output feedback designs for global asymptotic stabilization

International audienceThe design of output feedback for ensuring global asymptotic stability is a difficult task which has attracted the attention of many researchers with very different approaches. We propose a unifying point of view aiming at covering most of these contributions. We start with a necessary condition on the structure of the Lyapunov functions for the closed loop system. This motivates the distinction of two classes of designs: -the direct approach, also called control error model analysis, in which the attention is focused on directly estimating a stabilizer, and -the indirect approach, also called dynamic error model analysis, in which the stabilization task is fulfilled for an estimated model of the system and not directly for the system itself. We show how most available results on this topic can be reinterpreted along these lines